Due to the rapid progress of the optical and semiconductor technology, office machines, such as fax machines, copy machines, scanners, and printers, not only be reduced in size but also be increased in accuracy.
A laser printer is popular for printing original documents. A working theory of the laser printer is to uniformly spread electrostatic charge on a photo conductor drum and then expose the photo conductor drum to light streams to form a electrostatic latent image thereon. Subsequently, toners are attached on the photo conductor drum by way of an electric field action to reproduce a toner image and then the toner image is transferred to a paper.
A scanner is utilized to read documents, including texts and/or pictures. The scanner utilizes a light source to expose the documents under light streams and through a lens to accumulate reflected light streams on a charge coupled device (CCD) or contact image sensor (CIS) for transferring optical signals into electrical signals. The electrical signals are then transferred into digital signals with an analog/digital converter and finally these digital image data are stored to complete the scanning procedure.
A fax machine reads an image, such as texts and/or pictures, and sends the same to a remote fax machine to reproduce the image there. In addition, a copy machine reads an image and reproduces the image therein immediately. Because the above office machines include some overlapping functions, a multi-function office machine is designed to combine the above functions of the office machines into one machine. A popular multi-function office machine includes functions of a printer, a scanner, a copy machine, and fax machine.
For a current multi-function office machine, a flatbed scanner or a sheetfed scanner is normally utilized to read the image and a printer is utilized to output the image. Therefore, the multi-function office machine includes scanning and printing functions, and may further include copy and fax functions. The multi-function office machine combines multiple conventional office machines into one machine so as to reduce space requirements in an office. However, a conventional multi-function office machine still occupies a quite large area of an office desk.